# Crystalline iridium : computation of the total energy
#
# Determination of the surface energy of iridium  :
# Relaxation

#Definition of the unit cell
acell  3*7.29  # Lattice parameters of bulk iridium

rprim  0.5 -0.5  0.0    #unit cell consists of 5 Ir layers and 7 vacuum layers
       0.5  0.5  0.0    #interlayer distance 0.5acell
       0.0  0.0  6.0    
iprcel 45

#Definition of occupation numbers
occopt 4
tsmear 0.02

#Definition of the k-point grid 
kptopt 1          # Option for the automatic generation of k points, taking
                  # into account the symmetry
ngkpt  12 12 1  
nshiftk 2
shiftk  0.5 0.0 0.0
        0.0 0.5 0.0

#Definition of the atom types
ntypat 1          # There is only one type of atom
znucl 77          # The keyword "znucl" refers to the atomic number of the 
                  # possible type(s) of atom. The pseudopotential(s) 
                  # mentioned in the "files" file must correspond
                  # to the type(s) of atom. Here, the only type is Aluminum
                         

#Definition of the atoms
natom 5           # 5 atoms per cell: 5 aluminum layers and seven vacuum
typat 5*1         # These atoms are of type 1, that is, iridium
xcart            
     2*0 0
     0 2*3.645
     2*0 7.29
     0 3.645 10.935
     2*0 14.58
     
#Exchange-correlation functional
ixc 1           # LDA hgh

#Definition of the planewave basis set
ecut  30.0         # Maximal kinetic energy cut-off, in Hartree

#The relaxation
ionmov 3
tolmxf 5.0d-5
ntime 100

#Definition of the SCF procedure
iscf 3
nstep 100          # Maximal number of SCF cycles
toldff 5.0d-6